jQuery(function(){
   var caterpillar = $("#adv_slider");
   var objs = $("#adv_slider a");
   var cnt = objs.length;
   var is_moving = false;
   var position = 0;
   var min_position = 1 - cnt;

   if(cnt < 2) { $("#adv_prev,#adv_next").click(function(){return false;}); return; }

   var delta = parseInt($(objs).css("width"));

   $("#adv_next").click(function(){
      if(is_moving) { return false; }

      is_moving = true;

      if(position == min_position) position = 0;
      else position --;

      $(caterpillar).animate({marginLeft: position * delta}, 300, function(){
         is_moving = false;
      });

      return false;
   });

   $("#adv_prev").click(function(){
      if(is_moving) { return false; }

      is_moving = true;

      if(position == 0) position = min_position;
      else position ++;

      $(caterpillar).animate({marginLeft: position * delta}, 300, function(){
         is_moving = false;
      });

      return false;
   });

});